Transformer and circuit



L. J. BUTTOLPH TRANSFORMER ANUc RcUIT Jul 10, 1928. 1;676,768

Original Filed Jan. 24, 1923 iNVENTOR Patented July 10, 1928.

UNITED STATES- I 1,676,768 PATENT OFFICE.

LEROY J. BUTTOLPH, OF GRANTWOOD, NEW JERSEY, ASSIGNOR TO COOPER HEWITT ELECTRIC COMYANY, OI HOBOKEN, NEW JERSEY, A CORPORATION OF NEW JERSEY.

rnausronmnn AND omcurr.

Original application filed January 24, 1923, Serial No. 614,572. Divided and this application filed Kay 1,

1926. Serial No. 105,953.

The present invention relates to circuits and apparatus for operating electric devices.

The object of the invention is to prov de a compact unitary outfit capable of being produced cheaply and having wide commercial utility in that it is readily operable on commercial circuits of varying voltages, and on either alternating or direct current.

By way of illustration I have shown my invention in connection with the operatlon of electric lamps of the negative glow type shown and described in United States Patent No. 1,316,967 issued September 23, 1919, on an invention of D. McFarlan Moore, although it will be understood that the invention is not limited to electrically operated devices of this particular type, nor to the particular voltages mentioned.

In the accompanying drawings, Figure 1 is a diagrammatic view of the circuits and apparatus for operating electric devices on ordinary commercial circuits, either alternating current or direct current, and Figure 2 is a front elevation of a novel form of apparatus and circuits and electric lamps having utility as a portable sign.

Referring to the drawings, 1 and 2 represent the mains from a suitable source of electric current, either alternating current or direct current (not shown) and 3 and 4. are the coils of an auto-transformer. A work circuit 5, 6, is connected to the outer terminals of the auto-transformer and one or more negative glow lamps 7, 7. One of the two electrodes of a lamp 7 is larger than the other, the larger electrode being shaped to form a symbol, character, or alphabet letter, as may be desired. In the present instance, the larger electrode is formed as a letter of the alphabet, and as shown in Figure 2, four lamps are arranged in a portable sign outfit to spell the word EXIT. The inner terminals of said auto-transformer are connected together through a switch 8 a handle 9 to which extends through the floor 10 of the lamp chamber.

Each of the mains 1 and 2 is connected toits respective coils 3 and 4 of the auto-trans- .fo'rmer at point intermediate of said coil ends. The auto-transformer is wound on its closed core in the ordinary way, except that it is wound in two sections as nearly identical as possible, so that when the switch, 8 is open at any instant the current will be flowing in opposite direction in the two coils 3 and 4 and their magnetic fields will neutralize each other.

The connections for this device are designed so that the lamps can operate on low voltage alternating current on higher voltage alternating current or direct current. When operating on 110 volts alternating current for example the coils 3 and 4: operate as a step up auto-transformer, the switch 8 being closed. When only a higher voltage supply is available either alternating current or direct current the device is operated with the switch 8 open. An apparatus of this kind designed to operate at 110 volts alternating current can also operate at 220 volts alternating current or direct current, but my invention can be embodied in app-aratus operable at other voltages. When the device is operated at the higher voltage of alternative current, the switch 8 being open the current flows through a part of each of the coils 3 and 4 to and from the leads 5 and 6 of-the work circuit. The magnetic fields of these two coils, however, being in opposite directions, neutralize each other and the two coils being substantially symmetrical their impedance is negligible. When the device is used on direct current circuits of either 110 volts or 220 volts, or other suitable voltage, the switch 8 is opened, and the current flows through a part of the coils 3 and 4 from the mains 1 and 2 to the work leads 5 and 6, the coils offering negligible resistance to the flow of current and there is no lmpedance since the magnetic fields do not change.

In one embodiment of my invention I have used coils which are operable either at 110 volts alternating current or 220 volts alternating current or 110 volts or 220 volts direct current, and the only change neces- I sary is made through one switch, 8 as shown in the drawing, and this is closed for the low voltage alternating current and opened for the. 220 volts alternating current and for the direct current. The auto-transformer which I'use is of the closed core type with taps at the middle of each of the coils 3 and 4 to the respective mains 1 and 2. The outer ends of the coils are connected to the work leads 5 and 6, the inner ends of the coils being connected together through .a switch 8 which is at the mid-point of the auto-transformer when the coils operate as an auto-transformer. When the coils are used as an auto-transformer, they step u I the voltage from 110 to 220 volts. When 1t is desired to operate on 220 volt supply the switch 8 is opened and the current flows directly from t e mains to the lamps, the coils ofi'erln but negligible resistance. When 220 I volts alternating current is used the switch 8 at the mid-point of the auto-transformer being open, the magnetic fields of the two other suitable type of core.

This application is a division of my copending application Serial Number 614,572 filed January 24, 1923.

I claim:

1. In a system for controlling electrical apparatus in combination an auto-transformer having two coils which are electrically symmetrical, lead wires for the apparatus to be controlled, taps from the ends of the coils adapted to be connected to the apparatus leads, a switch between the two coils, taps from points'intermediate the ends of'each coil for connection with suitable feed mains.

2. In a system for controlling electrical apparatus, in combination, apparatus to be controlled, a closed-core auto-transformer having two coils which are electrically symmetrical, a lead from the outer end of each of the two coils to the apparatus controlled thereby, a supply main connected to an intermediate point on each of the coils, and a switch between the inner ends of the two coilswhereby when the same is opened and the apparatus used on higher voltage of alternating current and any voltage of direct current the magnetic fields thereof neutralize each other to produce negligible impedance.

Signed at Hoboken in the county of Hudson and State of New Jersey this 28th day of April, A. D. 1926.

LEROY J. BUTTOLPH'. 

